Identification of Potential Proteins Interacting with α-Galactosidase A to Analyze the Pathogenesis of Fabry Disease

The lysosomal enzyme α-galactosidase A (AGAL) degrades globotriaosylceramide (Gb3). While this enzymatic function in lysosomal metabolism is well characterized, interaction partners and alternative functions are unknown. This study aims to identify new potential AGAL-interacting proteins. AGAL was fused to the mutated biotin ligase BirA from E. coli (TurboID). Expression of the fusion protein was confirmed by Western blot and immunofluorescence, while enzymatic activity was verified by functional assays. In three experimental settings (AGAL wild-type (WT), AGAL missense variant (p.N215S), and the control cell line), TurboID-biotinylated proximal proteins were enriched by streptavidin pull-down and analyzed by mass spectrometry. Gene Ontology (GO) terms were subsequently evaluated to characterize biological functions and localizations of the identified proteins. Selected candidates were co-immunoprecipitated with AGAL to confirm direct interactions. The AGAL-TurboID fusion protein was successfully expressed in AB8/13 podocytes. Immunofluorescence and enzyme activity assays confirmed the presence and functionality of the fusion protein. Subsequent functional analysis (GO term analysis) showed enrichment of driver terms, including extracellular matrix organization (ECM), multicellular organism development, and protein metabolic process, in the biological process category. The identified top-hit proteins were predominantly involved in the organization of ECM, cell proliferation and cytokinesis, unfolded protein response during endoplasmic reticulum stress, and protein ubiquitination. Co-immunoprecipitation confirmed the interaction between AGAL and the candidate Galectin-3-binding protein (Gal-3BP). Our results suggest that AGAL may play a role in other pathways and/or the ECM organization beyond its lysosomal function. The confirmed interaction with Gal-3BP can now be functionally investigated in further studies.